In response to your questions: The begining of July is unfortunately not the best time for white water rafting. The water is still a bit to high so you will do a shorter High water run - I go into depth on the difference between the High and Low water runs on our rafting page which can be seen here Zambezi rafting. The Zambezi is always exciting and an adrenaline rush but at that time of year it's not considered the best one day rafting in the world. It's relative though so depends on what rafting you have done in the past and how much action you need to get an adrenaline kick.
The upper zambezi canoeing is by it's very nature more tame and peaceful, it's about taking in the beauty of the Zambezi, it's birds and wildlife. The small rapids you encounter are an added bonus but would not be considered as an adrenaline activity. Although coming close to hippo can get the adrenaline racing. For me at that time of year, there is no arguement. Go straight for the canoeing - the rafting is a washout.
You can walk on the bridge unguided but not underneath, to go underneath you will need to join a bridge tour.
Yes it is definately possible to view the Falls without a guide. Simply get to the entrance gate pay your entry fee and then follow the paths. It's all very clear, you wont miss a thing, only advantage of a guided tour is that you get picked up and dropped off from your hotel and that the guide will give you lots of information about the formation and history of the Falls which is very interesting.
The activities are the same price whether you book them in Vic Falls or beforehand. For example the cost of a helicopter flight is $140 whether you walk into the helicopter office in Victoria Falls, one of the hotels in the Falls or through us online before you get there. If you pay in rand with a credit card though you will likely incur credit card fees and a poor exchange rate. My suggestion is to arrange your activities beforehand, this way you are not wasting your holiday time trying to get things sorted out, sitting in booking offices, its just not worth it and doesn't save you any money. Activities can also get full and then you go away disappointed. If you book through us you can transfer into a bank account in SA and avoid credit card fees and get a better exchange rate.
I hope that I have managed to answer your questions and make things clearer for you.
